This invention relates to a latch which prevents the inadvertent disengagement of the horizontal support beams from the vertical support posts in a pallet type of rack or similar heavy duty, load supporting frame.
A pallet type rack, or similar support frame, is made of vertical support posts which are interconnected by horizontal beams. Shelf forming slats or sheets may be arranged upon and extend between opposing beams for supporting loads. Alternatively, the beams may be used alone, like shelves, with loads resting upon and spanning opposed beams. Loaded pallets or containers or similar large objects may be positioned upon the shelf forming slats or sheets or may be arranged upon the beams themselves. Thus, the rack or frame is, in essence, an open shelving arrangement.
In heavy duty pallet type racks or similar types of frames that are used to support heavy loads, the ends of the beams are adjustably connected to their respective posts. One form of connection which is conventionally used involves providing a series of vertically spaced apart holes in the posts. The posts are typically formed of roll formed sheet metal tubing. The holes are provided in one or more of the vertical faces of the tubing. For this purpose, the tubing may be square or rectangle or similarly configured in cross-section.
The ends of each of the beams are usually provided with an angle bracket having pins that interlock with the holes in the posts. That is, the beam ends are welded or bolted to one leg of the bracket. Another leg of the bracket is provided with several horizontal pins which extend through corresponding holes in the adjacent post for temporarily fastening the post and beam together. Conventionally the pins have enlarged heads and the holes in the posts are bayonet-slot or inverted teardrop in shape so that the heads may be inserted through the wide portions of the holes and the stems of the pins may be gripped in the narrowed portions of the holes.
The beams may be attached to the posts at different heights by inserting their pins through the post holes that are located at the desired height. When the pins are inserted, the beams drop down slightly so that the stems of their pins drop into the narrowed portions of their respective post holes. The heads of the pins prevent withdrawal from the holes. Conversely, the beams may be removed or disengaged simply by moving them upwardly a short distance so that the heads of their pins may pass through the widened portions of the holes for withdrawing the pins from the holes within which they are engaged.
Typically, the beams are formed of rolled sheet metal with square or rectangular or similarly configured cross-sectional shapes. Their ends may be suitably welded to the angle brackets. An example of this type of pallet rack or frame construction is disclosed in my prior Pat. No. 4,760,682, issued Aug. 2, 1988, for a tubular rack beam and method of making same.
Because the loads placed upon this type of heavy duty rack are substantial, it is common to use mechanical handling equipment, such as fork trucks, lift vehicles and the like. When this equipment is used, from time to time, the beams are jostled or pushed or struck by the equipment. Consequently, the beam ends may be raised sufficiently to cause their fastening pins to inadvertently disengage from the holes in which they are fitted. In that event, it is possible for the beam to fall out of position and to cause a load to fall off the rack or to undesirably shift position during loading or unloading. Thus, it is desirable to provide a suitable safety latching device which prevents the beam pins from inadvertently disengaging from their holes. However, such safety latches must be easy to use, inexpensive, and easily replaceable. The invention herein relates to a safety latch construction for use in preventing unwanted disengagement of the beams from the posts in a rack or similar frame type of construction.